Dietitians: Agave not an ideal sugar substitute

For health-conscious people, agave is a great alternative to sugar. But is it good for you? Here's why less is better."I was putting too much in my coffee and my grapefruit and I was under the impression that it was a 'good' sugar," said L.A. resident Marissa Smith.

Like many who are health-conscious, Smith uses agave as her sweetener because the nectar from the agave plant is low on the glycemic index, which means it does not spike blood sugar like table sugar or other sweeteners.

"However, that does not mean that it's good for you, and especially not good for someone with diabetes or at risk for diabetes," said Registered Dietitian Alyse Levine.

Levine says the chemical makeup of table sugar, even high-fructose corn syrup, is a near balance of half-glucose and half-fructose. But agave is made up of nearly all fructose.

"Fructose, when consumed in large quantities, can actually increase insulin resistance, which makes you more at risk for diabetes as well as increases your triglycerides, lower your good HDL cholesterol and a lot of other potentially harmful effects on your heart," said Levine.

"I think it's a triumph of marketing over science," said Dr. Jonny Bowden, an author of books on nutrition. "It's basically high-fructose corn syrup. It's even higher in fructose than high-fructose corn syrup."

Bowden uses agave oh-so-sparingly in foods, as he feels too much of it wreaks havoc on the body.

"Glucose, plain old sugar -- blood glucose -- gets metabolized by every cell in the body," said Bowden. "But fructose only gets metabolized by the liver. That's a big load for the liver."

Which he says could lead to fatty liver disease.

"Use a tiny bit of it but don't think this is a free pass," said Bowden.

Actually, since agave is sweeter than sugar, you can use less of it, something health experts wish manufacturers would pick up on.

"I haven't found manufacturers using less. I still find that they are going for an elevated level of sweetness," said Registered Dietitian Ashley Koff.

But do keep in mind consuming fructose in fruit, for example, is fine because you're also getting water, fiber and a host of nutrients as nature intended.